Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

Dynamic Array, Summaries of Computer science

Computer science

You will implement a DynamicArray ADT (Abstract Data Type), a C++ class that will allow us to use a dynamic integer array without worrying about all the ...

Typology: Summaries

2022/2023

Uploaded on 02/28/2023

heathl
heathl 🇺🇸

4.5

(11)

235 documents

1 / 5

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
The University of
Chicago
Department of
Computer Science
CMSC 15200 – Introduction to Computer Science 2
Dynamic Array
Dynamic Array
You will implement a DynamicArray ADT (Abstract Data Type), a C++ class that will
allow us to use a dynamic integer array without worrying about all the memory
management issues. To accomplish this, DynamicArray will have two private member
variables: a pointer to int (which will point to an array allocated in the heap) and the size
of the array. It is the responsibility of the DynamicArray class to correctly initialize these
private member variables and to make sure that they are always in a consistent state.
This dynamic array has the following characteristics:
➢Its positions are numbered starting with 0, like C/C++ arrays.
➢The array must grow to meet the user's needs. For example, if the user creates an
array of size 5, and the user then wants to assign a value to position 9, then
DynamicArray must automatically grow its size to 10.
➢The values in the array can only be non-negative integers.
➢Because the array can dynamically grow, there might be “empty positions”. For
example, if the user creates an empty array, assigns a value in position 0 and then
a value in position 4, the array will have size 5, but positions 1, 2, and 3 will be
“empty”. Empty positions will have value -1.
Page 1 of 5
pf3
pf4
pf5

Partial preview of the text

Download Dynamic Array and more Summaries Computer science in PDF only on Docsity!

Chicago

Department of

Computer Science

Dynamic Array

Dynamic Array

You will implement a DynamicArray ADT (Abstract Data Type), a C++ class that will

allow us to use a dynamic integer array without worrying about all the memory

management issues. To accomplish this, DynamicArray will have two private member

variables: a pointer to int (which will point to an array allocated in the heap) and the size

of the array. It is the responsibility of the DynamicArray class to correctly initialize these

private member variables and to make sure that they are always in a consistent state.

This dynamic array has the following characteristics:

➢ Its positions are numbered starting with 0, like C/C++ arrays.

➢ The array must grow to meet the user's needs. For example, if the user creates an

array of size 5, and the user then wants to assign a value to position 9, then

DynamicArray must automatically grow its size to 10.

➢ The values in the array can only be non-negative integers.

➢ Because the array can dynamically grow, there might be “empty positions”. For

example, if the user creates an empty array, assigns a value in position 0 and then

a value in position 4, the array will have size 5, but positions 1, 2, and 3 will be

“empty”. Empty positions will have value -1.

Chicago

Department of

Computer Science

Dynamic Array

The class declaration is the following (DynamicArray.h in the provided files):

class DynamicArray { private : int *a; int s; int grow( int s2); // Optional public : // Constructors DynamicArray(); DynamicArray( int s); DynamicArray( int *a2, int s2); DynamicArray( const DynamicArray &da); ~DynamicArray(); // Member functions int getSize(); // Already implemented int setValue( int pos, int v); int getValue( int pos, int &v) const ; // Operator overload DynamicArray& operator =( const DynamicArray &da2); bool operator ==( const DynamicArray &da2) const ; friend ostream& operator <<(ostream &os, DynamicArray &da); int & operator []( int pos); int operator []( int pos) const ;

(Note: The header file also includes some constant member variables not shown above)

To test your implementation, a main.cpp is provided. Running this program with a

correct DynamicArray implementation should yield the following:

FIRST ASSIGNMENT

Had to grow the array. SECOND ASSIGNMENT Had to grow the array. THIRD ASSIGNMENT Did not have to grow the array. ARRAY A1: 37 -1 7 -1 23 ARRAY A2: 42 42 42 42 42 ARRAY A3: 42 42 42 42 42 ARRAY A4: 42 42 42 42 42 ACCESSING VALUES Position 2: 7 Position out of range. COMPARISONS

Chicago

Department of

Computer Science

Dynamic Array

make your setValue implementation simpler, it might be useful to think of growing as a

separate operation:

/* Grows the array to size “s2”. This means copying the current array

  • to a new array of size “s2”, and filling all the new positions with
  • value -1 (empty positions).
  • / int grow( int s2);

Implementing the grow function is optional (you can just include all the growing code

inside the setValue function).

Also, notice that setValue must return a status code. These status codes are already

defined as constant member variables in class DynamicArray:

static const int SET_OK_NOGROW = 0; static const int SET_OK_GROW = 1; static const int SET_ERROR_NEGPOS = 2; static const int SET_ERROR_NEGVALUE = 3; Exercise 3 <<5 points>>

Implement the getValue function:

/* Returns the value in position "pos" using parameter "v".

  • The function must return the following:
  • 0: Success.
  • 1: Error. A bad position was specified. */ int getValue( int pos, int &v) const ; Exercise 4 <<10 points>>

Overload the assignment and equality operators:

/* Assignment operator overload / DynamicArray& operator =( const DynamicArray &da2); / Equality operator overload.

  • Returns true if both DynamicArrays are the same. We assume
  • that two DynamicArrays are the same if (a) they have the same
  • size and (b) they have the same value in every position. */ bool operator ==( const DynamicArray &da2) const ;

Chicago

Department of

Computer Science

Dynamic Array

Exercise 5 <<5 points>>

Overload the shifting operator to print a DynamicArray to an output stream:

friend ostream& operator <<(ostream &os, DynamicArray &da); Exercise 6 <<10 points>>

Overload the bracket operator:

int & operator []( int pos); int operator []( int pos) const ;

The bracket operator overload was not discussed in class, so you will have to read about

it on your own. You must overload the bracket operator in such a way that the user can

access a position in the dynamic array by using the bracket operator, instead of the

getValue function. For example:

int a[5] = {42,42,42,42,42}; DynamicArray a1(a,5); cout << a1[3]; // Prints out 42

Note that the bracket operator in this case is not as safe as the getValue function, as

there is no way of returning a status code telling if the specified position is valid or not.

So, if the user specifies an non-existing position, the bracket operator must return it,

regardless of whether it exists or not (this mimics the behaviour of C/C++ arrays).

Finally, notice how there are two bracket operator overloads. One is used when the

DynamicArray is used as an l-value, and the other one when it is used as an r-value (you

will have to figure out which is which!). The r-value version must simply return the value

in the specified position, while the l-value version might have to grow the array so the

position will be valid.

int a[5] = {42,42,42,42,42}; DynamicArray a1(a,5); cout << a1[3]; // R-Value version, prints out 42 a[1] = 5; // L-Value version, doesn't grow the array cout << a1[3]; // R-Value version, prints out 5 a[10] = 37; // L-Value version, has to grow the array